Method for sening residues using terahertz electromagnetic waves with high sensitivity and device used therefor

Abstract

Disclosed herein are a method and device for sensing pesticide residues, using terahertz electromagnetic waves. By the method, even a trace amount of pesticide residues on objects such as fruits can be accurately discriminated and sensed, with high sensitivity and selectivity, using a sensing chip that works in a terahertz electromagnetic wave band. Using the method, pesticide residues even at low concentrations can be accurately analyzed with high sensitivity and selectivity in which terahertz electromagnetic waves are irradiated onto pesticide residues through a sensing chip having a meta unit in which a pattern is formed to amplify a frequency corresponding to an absorption frequency of a pesticide residue of interest.

What is claimed is: 
     
       1. A method for sensitively and selectively sensing pesticide residues, using a sensing chip, wherein the sensing chip has a meta unit in which a pattern is formed for amplifying a frequency corresponding to an absorption frequency of a pesticide residue of interest, and wherein the sensing chip, when irradiated with terahertz electromagnetic waves, passes the waves therethrough to the pesticide residue of interest and amplifies waves reflected from the pesticide residue of interest, whereby the pesticide residue of interest can be analyzed for subtype even when it is present at a low concentration, wherein the method comprises:
 a target disposition step in which a pesticide residue of interest is disposed on a sensing chip having a meta unit in which a pattern is formed for amplifying a frequency corresponding to an absorption frequency of a pesticide residue of interest; 
 a light irradiation step in which terahertz electromagnetic waves are irradiated to the pesticide residue of interest on the meta unit; and 
 a target determination step in which the terahertz electromagnetic waves passing through the sensing chip are measured for transmittance or frequency change to specify the pesticide residue. 
 
     
     
       2. The method of  claim 1 , wherein the target determination step is adapted to measure the terahertz electromagnetic waves passing through the meta unit for transmittance or frequency change thus to specify pesticide residues and to determine concentrations of the specified pesticide residues, based on the fact that transmittance or a frequency change is elevated when the absorption frequency of a target pesticide residue corresponds to the resonant transmission frequency of the meta unit. 
     
     
       3. The method of  claim 1 , further comprising:
 a quantitative analysis step in which the pesticide residue of interest is quantitatively analyzed, based on a change of the transmittance and/or frequency of the terawave passing through the sensing chip with a concentration of the pesticide residue of interest. 
 
     
     
       4. The method of  claim 1 , wherein the pattern is in a form of slits, each ranging in width from 10 nm to 1 μm, in thickness from 100 nm to 1 μm, and in length from 10 μm to 1 mm. 
     
     
       5. The method of  claim 4 , wherein the pattern is an array of slits that is formed at regular gaps in the meta unit of 1 nm to 1 mm in a widthwise direction and 1 nm to 1 mm in a lengthwise direction. 
     
     
       6. The method of  claim 4 , wherein the metal unit of the sensing chip is formed on a flexible substrate whereby the sensing chip can be applied to a curved surface of an object. 
     
     
       7. A device for sensing pesticide residues, using the sensing chip used in the method of  claim 6 .